Textile electrodes as substrates for the electrodeposition of porous ZnO

Abstract

Metal-coated polyamide threads and filaments were chosen as substrate electrodes to deposit highly porous ZnO films for photovoltaic application. The films were electrodeposited at 70 degrees C from oxygen-saturated aqueous zinc salt solutions containing EosinY as a structure directing agent. The current density during deposition was increased compared with planar electrodes by enhanced diffusion at the filaments operating as cylindrical microelectrodes. Analysis by scanning electron microscopy showed an influence of geometrical constraints within the textiles and the hydrodynamic flow rate in the deposition solution on the film morphology. Photoelectrochemical characterization of sensitized films revealed the feasibility of the presented approach and indicated further steps needed for electrode optimization.

Textile‐Compatible Substrate Electrodes with Electrodeposited ZnO—A New Pathway to Textile‐Based Photovoltaics

“…The opening of the pore structure by desorption of eosinY (upper inset of Figure 3) is very clearly observed, as is the widely observed open pore structure following adsorption of D149 (lower inset of Figure 3). Despite the optimized mor- www.chemphyschem.org phology, optimized porosity and a sensitizer optimized for ZnO, the photoelectrochemical performance of these electrodes was not improved remarkably beyond the level reported for non-optimized electrodes, [8] even following deposition of a compact ZnO layer beneath these porous structures to block access of the redox electrolyte to the Ag electrode and hinder back-transfer of injected electrons and also Ag corrosion. Macroscopic cracks in the coating obviously still allowed access of the redox electrolyte, undermining a successful operation of the electrodes.…”

“…Under illumination by 100 mW cm À2 , similar to AM 1.5 conditions, a photocurrent density of about 1 mA cm À2 was measured under short-circuit conditions. [8] In spite of this first respectable success, cracks in the ZnO coating indicated problems in the coating reaction and allowed the iodine species to reach the Ag surface, thereby leading to unavoidable corrosion reactions.…”

“…[6,7] Porous crystalline ZnO could be prepared by electrodeposition from an oxygen-saturated aqueous solution of ZnCl 2 in the presence of eosinY as a structure-directing agent. [8] A significantly increased deposition current was measured when compared to the electrodeposition on planar substrates and was understood as a result of three-dimensional diffusion at the 70 mm-diameter wire, a typical microelectrode effect which is beneficial to the electrodeposition on textiles. As seen earlier on the planar substrates, the structure-directing eosinY that had led to a porous structure of ZnO could be removed by treatment in alkaline solutions and an N535 Ru complex could be adsorbed to yield a photoactive electrode.…”

Flexible Photovoltaic Textiles for Smart Applications

“…If textile materials are behaved as active textiles, the maximum electrode distance in the range of 100 µm has to be considered. Loewenstein et al, (2008) and Lincot et al, (1998) have used Ag coated polyamide threads and fibers to deposit porous ZnO as semiconductor material . The crystalline ZnO films were prepared in a cathodic electrodeposition reaction induced by oxygen reduction in an aqueous electrolyte in presence of Zn 2+ and eosinY as structure-directing agent [19][20] .…”

“…Loewenstein et al, (2008) and Lincot et al, (1998) have used Ag coated polyamide threads and fibers to deposit porous ZnO as semiconductor material . The crystalline ZnO films were prepared in a cathodic electrodeposition reaction induced by oxygen reduction in an aqueous electrolyte in presence of Zn 2+ and eosinY as structure-directing agent [19][20] . Bedeloglu et al, (2009) 21 were used nontransparent non-conductive flexible polypropylene (PP) tapes as substrate without use of ITO layer.…”